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Effects of processing conditions on the physico-chemical characteristics of titanium dioxide ultra-thin films deposited by DC magnetron sputtering
, Article Ceramics International ; Volume 41, Issue 6 , July , 2015 , Pages 7977-7981 ; 02728842 (ISSN) ; Sadeghian, Z ; Nemati, A ; Mohammadi, S. P ; Mozafari, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In this research, titanium dioxide (TiO2) ultra-thin films have been successfully obtained on lamina-glass substrates by thermal oxidation of DC magnetron sputtered titanium. The as-deposited and the annealed films have been characterized by different techniques. The X-ray diffraction (XRD) results revealed the amorphous structure of as-deposited titanium and anatase crystal structure for the annealed films. The atomic force microscopy (AFM) results showed that increasing the annealing temperature could lead to rougher and larger grain size in the films. Finally, the optical data and band-gap calculations of the films were obtained using the transmittance spectrum, indicating that...
Potential effects of alginate–pectin biocomposite on the release of folic acid and their physicochemical characteristics
, Article Journal of Food Science and Technology ; Volume 57, Issue 9 , March , 2020 , Pages 3363-3370 ; Alemzadeh, I ; Vaziri, A. S ; Beiroti, A ; Sharif University of Technology
Springer
2020
Abstract
Potential effects of folates on the treatment of several human diseases like cognitive function, neural tube defects, coronary heart disease and certain kinds of cancers have been discovered. However, the stability of folic acid against adverse conditions is a great concern. The present study investigates various alginate (A)–pectin (P) gastrointestinal-resistant hydrogel to immobilize folic acid. This involves evaluating different compositions of alginate–pectin to achieve higher encapsulation efficiency and stability during simulated gastric (SG) and simulated intestinal (SI) conditions. Coated alginate hydrogels with pectin resulted significant (p < 0.05) better protection of folic acid...
Synthesis of nZVI-Ni@BC composite as a stable catalyst to activate persulfate: Trichloroethylene degradation and insight mechanism
, Article Journal of Environmental Chemical Engineering ; Volume 9, Issue 1 , 2021 ; 22133437 (ISSN) ; Idrees, A ; Zaman, W. Q ; Abbas, Z ; Ali, M ; Rehman, M. S. U ; Hussain, S ; Danish, M ; Gu, X ; Lyu, S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In Fenton-like oxidation processes, the use of biochar (BC) as support material for the nanoscale zero valent iron-nickel (nZVI-Ni) bimetallic particles attained much attention to activate persulfate (PS) for TCE degradation in aqueous medium. In present work, nZVI-Ni@BC particles with nZVI-Ni to BC mass ratio of 1:5 exhibited excellent results (> 99 % ± 0.24) for TCE degradation. The physico-chemical characteristics, surface morphologies, and elemental mapping of the synthesized nZVI-Ni@BC particles investigated through SEM, EDX, TEM, XPS, XRD, BET and FTIR spectroscopy. For the nZVI-Ni@BC-persulfate system, the effects of PS concentration, initial pH, inorganic ions and natural organic...
Rheology, stability and filtration characteristics of colloidal gas aphron fluids: role of surfactant and polymer type
, Article Journal of Natural Gas Science and Engineering ; Volume 26 , September , 2015 , Pages 895-906 ; 18755100 (ISSN) ; Arabloo, M ; Ghazanfari, M. H ; Sharif University of Technology
Elsevier
2015
Abstract
Colloidal Gas Aphron (CGA) are finding increasing application in fields of science and engineering because of their distinctive characteristic. As interest in the application of CGA based fluids grows and in order to select the best procedure for using them in successful petroleum engineering operations, there is a need to gain a better understanding of the factors that affect their properties and behavior. This article discusses the rheological characterization, stability analysis and filtration properties of CGA based fluids for three bio-polymers and two ionic surfactant. The stability and filtration analysis were investigated with the static drain rate technique and API filtration tests,...
Relative and interactive effects of fluid's physicochemical characteristics on the incipient motion of a granular particle under laminar flow condition
, Article Journal of Hydraulic Engineering ; Volume 144, Issue 5 , 2018 ; 07339429 (ISSN) ; Gholizadeh Vayghan, A ; Adams, B. T ; Rajabipour, F ; Sharif University of Technology
American Society of Civil Engineers (ASCE)
2018
Abstract
This paper presents an experimental research for studying the relative and interactive effects of three physicochemical fluid characteristics (viscosity, pH, and ionic strength) on the incipient motion of a granular particle under laminar flow condition. Critical flow velocity for particle's incipient motion, an important factor for evaluating flow-induced soil erosion, was used to quantify the relative erosive capacity of the test fluids. Response surface methodology (RSM), a statistical design of experiments, was used to design and implement 20 test fluids with various levels of the three fluid characteristics. Incipient motion of a highly spherical glass bead positioned atop a specially...
Production of renewable hydrogen through aqueous-phase reforming of glycerol over Ni/Al2O3–MgO nano-catalyst
, Article International Journal of Hydrogen Energy ; Volume 43, Issue 2 , 2018 , Pages 614-621 ; 03603199 (ISSN) ; Kazemeini, M ; Larimi, A ; Maleki, H ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this study, a series of Ni nano-catalysts supported on Al2O3 and MgO were prepared through the co-precipitation technique. Effects of the Al/Mg ratio on physicochemical characteristics of Ni/Al2O3–MgO catalysts were examined. Moreover, catalytic performance was investigated in order to determine the optimum catalyst for H2 production in aqueous phase reforming (APR) of glycerol. It was revealed that, the APR activity of synthesized catalysts strongly depended on the aforementioned ratio. In addition, it was observed that, the catalytic activity of Ni/MgO and Ni/Al2O3 samples were both lower than that of the corresponding mixed oxide supports. Furthermore, it was shown that, amongst the...
Preparation of mesoporous nanostructure NiO–MgO–SiO2 catalysts for syngas production via propane steam reforming
, Article International Journal of Hydrogen Energy ; Volume 45, Issue 11 , 2020 , Pages 6604-6620 ; Kazemeini, M ; Farhadi, F ; Rezaei, M ; Keshavarz, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this research, the propane steam reforming (PSR) as a promising alternative route over a mesoporous NiO–MgO–SiO2 catalyst to produce syngas (SG) was undertaken. This catalyst was prepared using a co-precipitation method followed by hydrothermal treatment. The influence of such catalyst preparation factors as the hydrothermal time and temperature, pH and calcination temperature on the physicochemical characteristics of the prepared samples were examined. Next, these materials were characterized through the BET-BJH, XRD, TPR, and FTIR analyses. The thermal stability of this catalyst was tested through the TGA and DTA techniques. Furthermore, the deactivation of the calcined catalysts at...
Renewable hydrogen production by aqueous-phase reforming of Glycerol using Ni/Al2O3-MgO nano-catalyst: effect of the Ni loading
, Article Biomass Conversion and Biorefinery ; 2020 ; Kazemeini, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2020
Abstract
Aqueous-phase reforming (APR) of oxygenated hydrocarbons for hydrogen production presents several advantages as feed molecules might be easily found in a wide range of biomass; there is no need for its vaporization and the process allows thorough exploitation of the environmental benefits of using hydrogen as an energy carrier. In this contribution, catalysts with active phase Ni supported on Al2O3-MgO were synthesized at different loadings (1, 3, 5, 7, and 10 wt%) through the co-precipitation technique and tested for the Glycerol APR reaction. Effects of the Ni loading on physicochemical characteristics of Ni/Al2O3-MgO catalysts were examined. Moreover, catalytic performance was...
Effects of physicochemical characteristics of magnetically recoverable biocatalysts upon fatty acid methyl esters synthesis from oils
, Article Renewable Energy ; Volume 116 , 2018 , Pages 613-622 ; 09601481 (ISSN) ; Kazemeini, M ; Singh, G ; Arpanaei, A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
This study reports the importance of physicochemical characteristics of the core-shell structured polymer-coated Fe3O4 cluster@SiO2 nanocomposite particles for designing the biocatalysts used for transesterification of soybean oil. To demonstrate this issue, two different types of polymer molecules such as polyethylenimine (PEI) and polyacrylic acid (PAA) each with two different molecular weights are employed. The highest fatty acid methyl esters (FAMEs) synthesis yield values are achieved by the lipases immobilized onto the low- and high-molecular-weight PEI-coated particles as compared to those of the low- and high-molecular-weight PAA-coated particles (i.e., ∼64.8% and ∼73.1% versus...
Optimization of alginate-whey protein isolate microcapsules for survivability and release behavior of probiotic bacteria
, Article Applied Biochemistry and Biotechnology ; Volume 190, Issue 1 , 2020 , Pages 182-196 ; Alemzadeh, I ; Vaziri, A. S ; Vossoughi, A ; Sharif University of Technology
Springer
2020
Abstract
The present study aimed to improve the survivability of L. acidophilus encapsulated in alginate-whey protein isolate (AL-WPI) biocomposite under simulated gastric juice (SGJ) and simulated intestinal juice (SIJ). Microcapsules were prepared based on emulsification/internal gelation technique. Optimal compositions of AL and WPI and their ratio in the aqueous phase were evaluated based on minimizing mean diameter (MD) of the microcapsules and maximizing encapsulation efficiency (EE), survivability of cells under SGJ (Viability), and release of viable cells under SIJ (Release) using Box-Behnken experimental design. Optimal composition comprising 4.54% (w/v) AL, 10% (w/v) WPI, and 10% (v/v)...